竖向混合结构钢柱脚抗震性能试验研究

Experimental Study on Seismic Performance of Vertical Hybrid Structure Column Base

低层或多层既有建筑数量较多,对其直接进行加层改造已成为完善建筑使用功能、增加使用空间的重要手段。钢结构具有自重小、构造灵活、施工方便等优点,在既有建筑加层改造工程中得到广泛应用。针对既有混凝土框架结构上部直接进行钢结构加层工程中常用的柱脚连接方式,按照实际工程施工流程,在既有混凝土结构上打孔,通过植入化学锚栓的方式固定上部钢柱脚,分别设计制作钢柱脚四周设置加劲肋的强连接柱脚节点试件和钢柱脚四周无加劲肋的弱连接柱脚节点试件,通过拟静力试验对试件抗震性能进行对比分析。研究结果表明,强连接与弱连接柱脚节点破坏形式相同,均为锚栓拔出破坏,上部钢柱脚均处于弹性工作状态;强连接柱脚节点峰值承载力相对于弱连接柱脚节点峰值承载力提高了193%;强连接柱脚节点耗能能力相对于弱连接柱脚节点有所增强,但耗能系数减小。

There are a large number of low⁃rise or multi⁃storey existing buildings in our country,and it is an important means to improve the use function and obtain the use space to directly add floors to them.Steel structure has many advantages,such as light weight,flexible structure and convenient construction,so it has been widely promoted and applied in the existing construction projects.In this paper,for the existing concrete frame structure,the column base connection method commonly used in the steel frame layering project is adopted.According to the actual construction process,the upper steel structure column base is fixed by planting chemical anchors through drilling holes in the existing concrete structure,and the specimens of strongly connected steel column base with stiffening ribs around the steel column and weakly connected steel column base without stiffening ribs around the steel column are designed and produced respectively.The seismic performance of the two specimens was compared by pseudo static tests.The research results show that the failure forms of the steel column base specimens with strong connection and weak connection are the same,and the anchor bolt is pulled out,and the upper steel column base is in elastic state.The bearing capacity of the steel column with strong connection is increased by 193%compared with that of the steel column with weak connection.The energy dissipation capacity of the steel column with strong connection increases compared with that of the steel column with weak connection,but the energy dissipation coefficient decreases significantly.